From 4e76d6907ec1e8f065f7af3e4032e4b8cee6b2c1 Mon Sep 17 00:00:00 2001 From: Steven Moreland Date: Wed, 2 Oct 2024 00:37:59 +0000 Subject: libbinder: Parcel: validate read data before write This is slow, but it's required to prevent memory corruption. Ignore-AOSP-First: security Bug: 370840874 Test: fuzzer Merged-In: Ibc5566ade0389221690dc90324f93394cf7fc9a5 Change-Id: Ibc5566ade0389221690dc90324f93394cf7fc9a5 (cherry picked from commit c54dad65317f851ce9d016bd90ec6a7a04da09fc) --- libs/binder/Parcel.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp index 58b0b35323..2ddfdd727d 100644 --- a/libs/binder/Parcel.cpp +++ b/libs/binder/Parcel.cpp @@ -888,6 +888,10 @@ restart_write: //printf("Writing %ld bytes, padded to %ld\n", len, padded); uint8_t* const data = mData+mDataPos; + if (status_t status = validateReadData(mDataPos + padded); status != OK) { + return nullptr; // drops status + } + // Need to pad at end? if (padded != len) { #if BYTE_ORDER == BIG_ENDIAN @@ -1405,6 +1409,10 @@ status_t Parcel::writeObject(const flat_binder_object& val, bool nullMetaData) const bool enoughObjects = mObjectsSize < mObjectsCapacity; if (enoughData && enoughObjects) { restart_write: + if (status_t status = validateReadData(mDataPos + sizeof(val)); status != OK) { + return status; + } + *reinterpret_cast(mData+mDataPos) = val; // remember if it's a file descriptor @@ -1621,6 +1629,10 @@ status_t Parcel::writeAligned(T val) { if ((mDataPos+sizeof(val)) <= mDataCapacity) { restart_write: + if (status_t status = validateReadData(mDataPos + sizeof(val)); status != OK) { + return status; + } + memcpy(mData + mDataPos, &val, sizeof(val)); return finishWrite(sizeof(val)); } -- cgit v1.2.3-59-g8ed1b